Pneumatic hammer.



liNiTEn STATES Patented December 6, 1904.

MAX MAXIMILIAN, OF BUFFALO, NEW YORK.

PNEUMATIC HAMMER.

SPECIFICATION forming part of Letters Patent N o. 776,671, datedDecember 6, 1904. Application filed April 13, 1904. Serial No. 202,902.(No model.)

l To al?, whom it may concern.-

Be it known that I, MAX MAXIMILIAN, a subject of the Emperor of'Germany,residing' at Buifalo, in the county of Erie and State of New York, haveinvented new and useful lmprovements in Pneumatic Hammers, of which thefollowing' is a specification.

This invention relates to pneumatic hammers of that class in which thereversing-valve moves axially with reference to the piston.

The objects of this invention are to improve the construction of thereversing-valve mechanism, so as to increase the number of strokes ofthe piston within a given time and to permit of making' repairs easilyand also to provide simple and eiiicient means forautomatically-lubricating the working' Vparts of the hammer.

In the accompanying drawings, consisting' of two sheets, Figure L1 is alongitudinal section of my improved pneumatic hammer, the ports andpassages being shown diagrammatically for convenience in illustrating'the invention. Fig. 2 is a fragmentary view similar to Fig'. 1, showingthe reversing-valve in a shifted position. Figs. 3 and 4 arecrosssections in lines 3 3 and 4 4L, Figs. land 2, respectively.

Similar letters of reference indicate corresponding parts throughout theseveral views.

A represents the main or power cylinder of the hammer; B, the pistonreciprocating' therein; C, the tool or die fitted in the lower or rearend of the cylinder; D DQ the front and rear sections of thereversing-valve chest mounted on the front end of the cylinder; E, thehead or cap inclosing the Valve-chest and having a screw connection withthe cylinder, and F the handle applied to the outer side of the cap.Above the upper section of the valve-chest the cap is provided with anair-distributing chamber G, and the handle is provided with a passage(j, which connects the distributingehamber with a tube or other conduitthat supplies compressed air. This passage may be controlled by athrottle-valve of any suitable construction, that shown in the drawingsconsisting of a plunger H, arranged in an opening which intersects thesupply-passage g and having a reduced part or neck L, a spring t,whereby the plunger is normally shifted lengthwise, so that its fullpart closes the supply-passage, and a trigger or thumb-piece 7b2,whereby the plunger may be shifted to bring its contracted part in linewith the supplypassage for opening the same and admitting air into thedistributing-chamber.

The valve mechanism for alternately admitting the compressed air andexhausting' the spent air `from opposite ends of the cylinder forcausing the piston to reciprocate therein is constructed as follows:fithin the rear or `lower section of the valve-chest is formed avalve-chamber composed of a large upper or front part .l and asmall-lower or rear part l. The side walls of the upper and lower partsof the valve-chamber are constructed to form cylindrical valve-seats,which are preferably axially in line or parallel with the axis of thepower-cylinder. The top or outer end of the large valve-chamber isformed by the upper or front section of the valve-chest, while thebot-tom of the lonf'erchamber is formed bythe solid lower part of thelower section. The distributi11g-valve, which reverses the connection ofthe ports leading' to opposite ends of the power-cylinder, consists of alarge-area valve-piston J, arranged in the upper or large part of thevalve-chambcr, and a small-area \f'alve-1'Iiston J", arranged in thelower or small part lof the valve-chamber and connected with thelarge-area mlve-piston by a contracted neck or reduced party'. Thecompressed air is preferably conducted to the lower end of the smallpart of the valve-chamber by a plurality of passages f, cach of whichconsists of a longitudinal part extending from the distributing-chamberdownwardly through both valve-chest sections outside of thevalve-chamber, and a transverse part extending from the lower end of thelongitudinal part to the lower end of the valve-chamber. The inner orlower ends of the several passages all terminate in a main port 7:',which opens upwardly into the central part of the valvechamber at thelower end thereof. That pal't of the bottom of the valve-chamber aroundthe lower central air-inlet forms an annular shoulder with which themarginal part of the lower end of the distributing-valve engages in thelowered position of the same. A short distance above the lower end thesmall part of the valve -chamber is provided with an annularreversing-port which is connected by a plurality of obliquereversing-passages L with the upper end of the power-cylinder. Thesepassages open through the lower side of the valve-chest, so as toconnect the port l directly with the upper end of the cylinder and servealternately as air-supply conduits and as exhaust-conduits for this endof the power-cylinder. Above the port Z the small part of thevalve-chamber is connected with the atmosphere by a pluralityT ofexhaust-passages m, each of which consists of a transverse part arrangedin the lower section of the chest and opening at its inner end into thesmall part of the valve-chamber, and a longitudinal part extending fromthe outer end of the transverse part through the side of the lowerchest-section and the power-cylinder and opening into the atmosphereadjacent to the lower end of the cap, as shown in Fig. l.

In vthe elevated position of the distributing or reversing valve (shownin Fig. l) its lower piston is arranged between the inner end of theexhaust-ports m and the reversing-port Z, whereby the passages 71: and Lare connected, and compressed air is conducted into the upper end ofthepower-cylinder for propelling the piston downwardly or forwardly witha working stroke. In the depressed position of the reversing-valve(shown in Fig. 2) its lower or small piston is arranged below thereversing-port Z, whereby the passages L are connected with theexhaust-passages m, and

\ the spent air in the upper end of the cylinder is permitted to ventinto the atmosphere during the subsequent upward or idle return strokeof the piston.

Vhile the piston is moving forward or downward with a working stroke theair in front of the same is freely displaced into the atmosphere throughthe exhaust-passages N N. rIhe exhaust-passage N has a port n, whichopens into the lower part of the powercylinder at a distance from itslower end, while its outer end opens into the atmosphere, preferably bycommunicating with one of the exhaust-passagesm. The exhaust-passage N'communicates at its lower end with the extreme lower end of thepower-cylinder by a port a', while its upper end connects with the upperlarge part of the valve-chamber by a port n2, which opens through thelower part of the large cylindrical valve-seat thereof. During thedescent of the piston while the reversing-valve is elevated, as shown inFig. l, part of the air below the same is expelled directly to theatmosphere through the exhaust port and passage a N and part of itindirectly to the atmosphere by passing successively through the porta', passage N', port n?, upper and lower parts I I of the valve-chamber,and exhaust-passages m. The port n of the exhaust-passage is so locatedthat the same is covered by the piston during the last part of itsdownward or forward stroke, whereby the final portion of the air belowthe piston is expelled from the power-cylinder solely through thereversing-passage N and exhaust passages and ports connected therewithand prevents cushioning of the blow of the piston against the tool.

Then the piston reaches the lower end of its working stroke, its rearend has passed below a reversing-port 0, which connects by a passage 0'twith a port 02, opening' into the top of the upper large part of thereversing-valve chamber, this passage being formed partly in thecylinder and the two sections of the valvechest, as shown. The instantthe piston uncovers the reversing-'port 0 the compressed air passes fromthe cylinder upwardly through passage 0 and into the upper large part ofthe valve-chamber and exerts a downward pressure against the top of theupper valve-piston. Inasmuch as the pressure of the air against the topof the large-area valve-piston preponderates over the vair-pressureagainst the under side ofy the small-area valve-piston, these pistonsare shifted from the elevated position shown in Fig. 1 to the depressedposition shown in Fig. 2. Vhen this occurs, the connections ofthecompressed air and the exhaustair are reversed for causing the piston tobe raised by admitting compressed air underneath the piston andexhausting the spent air above the piston into the atmosphere. For thispurpose air inlet and exit ports p p are provided, which open throughthe upper part ofthe large cylindrical piston-valve seat, preferably ondiametrically opposite sides thereof, and connect, respectively, .withone of the airpassages it' and the passage N.

When the reversing-valve is in its depressed position, the compressedair passes from one of the passages throughthe inlet-port p,

thence across the valve-chamber above the upper valve-piston, thence outthrough the outlet-port p into the passage N', and thence into the lowerend of the cylinder, thereby lifting' or moving the piston therein witha return stroke. The full force of the compressed airis directed againstthe piston during the first part of its return or upward movement. Theinstant, however, that the piston has moved backwardly or upwardlysufliciently to uncover the exhaust-port 7L the force 0f the compressedair, leading to this end of the power-cylinder, is weakened to such anextent that the compressed air, which constantly presses upwardlyagainst the smallarea valve-piston, now preponderates overthe downwardpressure exerted against the largearea valve-piston, whereby thereversingvalve is shifted from the depressed position shown in Fig. 2 tothe elevated position shown in Fig, l. During the first part of theupward movement Qf the piston the air in the upper IOO ILO

part of the cylinder is expelled through the passages L, port Z. andpassages m; but du ring' the last part of this movement the compressedair enters the upper end of the cylinder, owing to the reversal of thevalve, thereby causing the piston to be cushioned at the end of itsupward movement and avoiding jarring of the hands of the operator who isholding' the tool.

When the valve has been thus reversed, the

operation ofthe parts is repeated continuously in the manner beforedescribed while the throttle-valve is open.

By forming an annular shoulder at the bottom of the valve-chamber aroundthe central air-inlet the area of the lower end of the smallvalve-piston which is exposed to the air-pressure is less than when thevalve is slightly raised, thereby enabling' the valve to be heldsecurely in its lowered position and. permitting the piston to completeits downward stroke and deliver an effective blow, but permitting thevalve to be reversed quickly an instant after the same has started inits upward movement.

The valve-pistons are preferably constructed in the form of cups, thelower small one opening downwardlynand the upper large one openingupwardly. By this construction of the reversing-val ve the compressedair entering the lower end ofthe valve-chamber centrally through themain port;I and air entering the upper end of the valve-chamber throughthe port o2 is caused to spread uniformly over the entire area of thesepistons and move the same up or down in a straight line without anytendency to tilt the same, which would cause the valve to wearunnecessarily and also reduce the efficiency of the hammer.

By arranging the outlets of the exhaustpassages adjacent to the lowerend of the cap the same are not liable to be closed by the hand of theoperator and cause interference with the working' of the hammer, nor `isthe workman so liable to be spattered with oil or other material whichmay be ejected by the blast of the escaping air.v as would be the caseif the exhaust-outlet were in the cap.

By making the upper seat of the reversingvalve wholly in the lowersection of the valvechest the upper valve-piston can be ground moreaccurately to its seat.

In order to prevent the reversing-valve from getting stuck on thedead-center by grit or other impurities in the air, and thus leaving thetool in a balanced and inoperative condition, one or more springs g areprovided, which tend constantly to move the reversing-valve toward oneend of its stroke. As shown in Figs. l and 2, these springs are arrangedbetween the upper valve-piston and the top of the valve-chamber andoperate to hold the reversing-valve yieldingly in its lower position..ln this position of the reversing-valve the ports are so connected thatair is admitted to the lower end of the cylinder for beginning theoperation of the piston with a liiaclnvard. stroke. By means of thesesprings the valve can never become stuck at a place where it is about toreverse the air connections of the cylinder, thereby avoiding loss oftime incident to adjusting' tools as ordinarily constructed in whichthis dilliculty frequently occurs. The reversing-port o2 at the upperend of the valve-chamber is made somewhat smaller than the port yf, sothat the air entering through the inlet-port y) and moving in thedirection of least resistance will favor the port p, from which lattert-he air passes to the cylinder underneath the piston, therebypreventing the air from being lead backwardly through the port 02 andpassage o' into the cylinder above the piston and balancing the pressureon the piston.

For continuously supplying lubricant to the hammer whenever the same isin operation lubricating means are provided which are operatedautomatically and are controlled by the working parts of the hammer,such as the re-,

versing-valve or the piston. The preferred. means for this purpose(shown in the drawings) comprises a reservoir or chamber R, arranged iuthe upper section of the valve-chest and having an open top throughwhich the same is filled with. lubricant, such as oil or grease, thisopening' being normally closed by a screw plug or cover r. ln its bottomthe reservoir is provided with a discharge-opening t', which leads intothe upper end of the valve-chamber and which is constructed at its upperend to form a conical valve-seat. l represents a conical feed-valvearranged in the reservoir and movable axially toward and from the seatin the opening s for controlling the discharge of lubricant. Thislubricatingvalve is moved downward against its seat for IOO closing theopening s by means of a spiral I spring t, seated at its opposite endson a boss t', formed on the upper end of the oil-valve, and a similarboss rfi, formed on the under side of the reservoir-cover. Thelubricatingvalve is provided at its lower end with a depending stemwhich projects downwardly into the reversing-valve chamber. On the upperside of the reversing-valve is arranged a tappet u, which adapted toengage the lower end of the stem of the lubricatingvalvc and lift thelatter from its seat during every upward movement of the same and leavessaid stem to permit the lubricating-valvc to engage its seat during cachdownward nievement of the reversing-valve. By this means thelubricating-valve is momentarily opened during every reciproeation ofthe reversingvalve, and small quantities of oil are continuouslysupplied to the working parts of the hammer, thereby insuring ypositiveand uniform lubrication thereof with a minimum amount of oil. The tappet'a preferably consists of a screw which engages with a threaded opening'in the large-area valve-piston and IIO has its head arranged in the neclof the reversing-valve, which is made hollow for this purpose. Byconstructing the tappet in the form of a screw the same can be readilyadjusted for regulating the amount of oil, which is suppliedintermittently, and the wear upon the parts may also be convenientlytaken up.

I claim as my invention- 1. A pneumatic hammer comprising apower-cylinder, a valve-chest having an integral bottom and a separabletop and containing a valve-chamber having a large upper cylindricalvalve-seat, a small lower cylindrical valve-seat, a lower main air-inletport opening` centrally into the lower end of said chamber, an annularshoulder formed at the lower end of said chamber around said centralinlet-port thereof, an intermediate main airinlet port opening into thesmall valve-seat above said lower central inlet-port and connected byoblique passages with the upper end of the cylinder, an exhaust-passageopen- `ing into the lower valve-seat above said intermediate port, anupper main air-inlet port connecting the upper part of said largevalveseat with the air-sup ply, another upper main air-inlet portconnecting the upper part of said large valve-seat with the lower end ofsaid cylinder and an upper exhaust-port connected with the lower part ofsaid large valveseat, and an imperforate main distributingvalve arrangedin said chamber and having a lower small valve-piston constructed in theform of a downwardly-opening cup and coperating with said smallvalve-seat for connecting said main lower air-inlet port either with themain intermediate air-port or with said lower exhaust-port and having'the marginal part of its lower end constructed to bear against saidannular shoulder, and an upper large valve-piston constructed in theform of an upwardly-opening cup and cooperating with said upper largevalve-seat for connecting said main upper air-inlets or said upper andlower exhaust-ports, substantially as set forth.

2. A pneumatic hammer comprising a powercylinder, a valve chestcontaining a valve-chamber and ports for connecting' opposite ends ofsaid cylinder with the air-supply and withthe atmosphere, a valvecontrolling said ports,and a spring bearing constantly against the valveand operating to yieldingly hold said valve at one end of its movement,substantially as set forth.

3. A pneumatic hammer comprising a power-cylinder, a valve-chest having'a chamber containing a large upper cylindrical valveseat, a small lowercylindrical valve-seat and ports connecting' opposite ends of thecylinder with an air-supply and with the atmosphere, a valve controllingsaid ports and having a large upper valve-piston which cooperates withsaid upper valve-seat for controlling' the admissionl and exhaust of airfrom the lower end of the cylinder, and a lower small valve-piston whichcooperates with the lower valve-seat for controlling the admlsslon andexhaust of air from the upper end of the cylinder, and a spring` bearingconstantly at its opposite ends against the upper end of said valve andthe top of the valve-chamber and operating to hold the valve yieldinglyin its depressed position, substantially as set forth.

4. A pneumatic hammer comprising a power-cylinder, means for controllingthe air connections with said cylinder comprising a valve-chamber and adistributing-valve reciprocatin g in said chamber, an oil-reservoirhaving an outlet which opens into the top of said chamber, and alubricator-valve which controls said outlet-opening' and which isengaged by the upper end of said distributing-valve during every upwardstroke of the same for lifting the lubricator-valve from its seat,substantially as set forth.

5. A pneumatic hammer comprising a power-cylinder, a piston, avalve-chest having a valve-chamber in its lower part, alubricatorreservoir in its upper part and a lubricatordischarge openingarranged in the bottom of the reservoir and opening into said chamber,an air distributing valve arranged in said chamber and operating' toconnect the opposite ends of said cylinder alternately with theair-supply and with the atmosphere, a lubricator-valve cooperating witha seat in said discharge-opening for controlling the escape of lubricantfrom the chamber and having a stem at its lower end and a boss at itsupper end, a cover applied to said reservoir and having a boss on itsunder side, a spring {itted at its ends on the bosses of saidlubricator-valve and cover, and a tappet cooperating with the stem ofsaid lubricator-valve for opening the same and consisting of a screwarranged on the airvalve, substantially as set forth.

Witness my hand this 9th day of April, 1904.

MAX MAXIMILIAN.

Witnesses:

THEO. L. Porr, EMMA M. GRAHAM.

IOO

